1. Field of the Invention
The present invention relates to weather strips attached to door window frames of vehicles for guiding door windows and methods of forming such weather strips.
2. Description of the Related Art
Weather strips, with which door windows engage, are typically attached to door window frames of vehicles. The weather strip guides the door window and seals between the door window frame and the door window against rainwater or the like. A typical weather strip 109 is shown in FIG. 15. The weather strip 109 includes front and rear side parts 101 shown in FIG. 15(a), an upper part 102 shown in FIG. 15(b), and a connecting part (not shown). The connecting part connects the side parts 101 with the upper part 102. FIGS. 15(a) and 15(b) are cross-sectional views showing the side part 101 and the upper part 102, respectively. The side part 101 includes an inner seal lip 104 and an outer seal lip 105. The inner seal lip 104 resiliently contacts an inner surface 103a of the door window 103 at a front or rear edge. The outer seal lip 105 resiliently contacts an outer surface 103b of the door window 103 at a front or rear edge.
An auxiliary lip 106 extends from the proximal portion of the outer lip 105. The auxiliary lip 106 reduces whistling of wind passing through a clearance 110, which is defined between the door window 103 and the outer seal lip 105. Furthermore, the auxiliary lip 106 improves the rigidity of the outer seal lip 105 and prevents the outer seal lip 105 from deforming toward the exterior of the vehicle when the window 103 moves. The side part 101 is extruded to have a uniform cross section.
The structure of the upper part 102 is almost the same as that of the side part 101 except for the auxiliary lip 106. The upper part 102 includes an inner seal lip 107 and an outer seal lip 108. The inner seal lip 107 resiliently contacts the inner surface 103a of the door window 103 at an upper edge, while the outer seal lip 108 resiliently contacts the outer surface 103b of the door window 103 at the upper edge.
No auxiliary lip 106 extends from the outer seal lip 108. This prevents the window 103 from catching the auxiliary lip 106 while moving upward between the inner seal lip 107 and the outer seal lip 108. The inner seal lip 107 of the upper part 102 is larger than the inner seal lip 104 of the side part 101. This improves the rigidity of the inner seal lip 107. The inner seal lip 107 is also resilient to guide the window 103, which moves upward between the inner seal lip 107 and the outer seal lip 108, to a predetermined position indicated by the double dotted chain line in FIG. 15(b). The upper part 102 is also extruded to have a uniform cross section.
The connecting part corresponds to a corner of the window 103 and connects the side part 101 with the upper part 102. The connecting part 101 is formed through injection molding or the like.
The weather strip 109 includes at least three members, that is, the front and rear side parts 101, the upper part 102, and the connecting part. Manufacture of these members requires independent molds, such as an extruder and an injection molding for separately forming the side parts 101, the upper part 102, and the connecting part. Furthermore, to form the weather strip 109, the front and rear side parts 101, and the upper part 102, each of which has been extruded independently, must be connected to one another by the connecting part (at the front upper corner and the rear upper corner). Therefore, at least four types of molds (two types of extrusion molding dies and two types of injection molds) are necessary to manufacture the conventional weather strip 109. This complicates the manufacturing equipment. Furthermore, since four or more parts must be formed separately, the number of manufacturing steps is increased.